use go1.18 to build gitea (#19099)

* use go1.18 to build gitea& update min go version to 1.17

* bump in a few more places

* add a few simple tests for isipprivate

* update go.mod

* update URL to https://go.dev/dl/

* golangci-lint

* attempt golangci-lint workaround

* change version

* bump fumpt version

* skip strings.title test

* go mod tidy

* update tests as some aren't private??

* update tests

.golangci.yml

@@ -13,7 +13,7 @@ linters:
     #- gocyclo # The cyclomatic complexety of a lot of functions is too high, we should refactor those another time.
     - gofmt
     - misspell
-    - gocritic
+    #- gocritic # TODO: disabled until fixed with go 1.18
     - bidichk
     - ineffassign
     - revive
@@ -64,7 +64,7 @@ linters-settings:
       - name: modifies-value-receiver
   gofumpt:
     extra-rules: true
-    lang-version: 1.17
+    lang-version: 1.18
 
 issues:
   exclude-rules:
@@ -152,3 +152,5 @@ issues:
     - path: models/user/openid.go
       linters:
         - golint
+    - linters: staticcheck
+      text: "strings.Title is deprecated: The rule Title uses for word boundaries does not handle Unicode punctuation properly. Use golang.org/x/text/cases instead."